| 摘要 |
PROBLEM TO BE SOLVED: To provide a brush device whose rear end surface is protected from flaws which cause abnormal noise. SOLUTION: A guide groove which is formed in a brush case and guides one end of a torsion spring has a tapered part. The one end of the torsion spring is pressed against the tapered part first, and then immediately after the one end of the torsion spring is made to straddle over the tapered part, the one end of the torsion spring is pressed against the rear end surface of a brush. Using such a constitution, both of an initial overload and a speed of the one end which are applied to the rear end of the brush are reduced.
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